The purpose of this research project is: 1) To resolve the heterogeneity of persons identified as deviant on our scale of psychosis proneness by studying their characteristics. Specifically, we will study handedness, foot preference, and cerebral lateralization of the subjects to learn if hypothetically psychosis-prone subjects who differ on these variables have other characteristics consistent with either schizophrenia proneness or proneness toward affective disorder. 2) To study a neglected symptom of some psychotics and of some nonpsychotics who appear psychosis prone. This symptom is episodic sinistrality, that is, episodes of left handedness in persons who are usually right-handed. Possibly this symptom may mark a usufel syndrome of psychosis and of psychosis proneness. Up until now, we have measured hypothetical psychosis pronemess by scales measuring Physical Anhedonia, Perceptual Aberration, Magical Ideation, and Nonconformity. We now are seeking ways to reduce false positives and to identify subjects at especially high risk. We also seek markers of proneness toward different psychoses. We have found that the groups of subjects who score high on two of our scales of psychosis proneness, the Perceptual Aberration - Magical Ideation Scale and the Nonconformity Scale, have, like schizophrenics, an excess of subjects who are nonright-handed, that is, are left-handed or ambilateral. The excess of left handedness among both schizophrenics and the psychosis-prone may reflect the presence of a subgroup who are brain damaged. We will, therefore, study the differences between right-handed and nonright-handed psychosis-prone subjects on measures of cerebral laterality, as well as on psychotic symptoms, social adjustment, and other symptoms.